What it means
Birch is the pioneer tree. After the last Ice Age it was among the first trees to move back onto bare ground, and it is still one of the first to take over cleared land, burnt heath or an old quarry. Tree calendar writers read Birch people the same way: they go first, set the standard and keep climbing after setbacks that would stop other people. They tend to be disciplined and a little reserved, with high expectations of themselves. Under the cool surface there is usually a lot of warmth for the few people they let close.
Strengths
Ambition, staying power after a fall, a willingness to go first into new ground, self-discipline, and calm in a crisis.
Challenges
Being hard on yourself, a cool manner that keeps people at arm's length, trouble resting once a goal is in sight, and measuring your worth by what you have achieved.
Birch dates and Ogham letter
Birch runs from December 24 to January 20 (28 days). Its Ogham letter is Beith, the letter for the sound B. The dates come from the tree calendar Robert Graves set out in The White Goddess (1948): thirteen 28-day months named after Ogham letters in his Beth-Luis-Nion order, plus one spare day, December 23. It is a modern system inspired by the Ogham, not a calendar recorded from the ancient Druids, and scholars think only some of the Ogham letter names first meant trees. Almost every Birch birthday has a Capricorn Sun. The Sun reaches Aquarius around January 20, so the last day or two of Birch can be Aquarius.
The birch in folklore
Birch twigs were the usual material for besom brooms, and the bright white bark made the tree an easy symbol of a clean start. Medieval Irish tradition says the very first message ever written in Ogham was seven strokes of the letter B cut into a birch rod, a warning sent to the god Lugh. So the calendar opens with the letter the alphabet itself was said to begin with.
How Cosmic Array reads it
Your tree depends only on the day and month you were born, so the year and birth time don't change it. The Architect blueprint shows your Celtic tree next to your Chinese animal, Mayan sign and Egyptian deity, and its written synthesis can set the tree against your Western Sun, Moon and Rising.